The C-Bill originated from early ComStar's Letter of Credit[2], which detailed the value of ComStar's communication services to the Great Houses and the public. Approved in 2835 the C-Bill was intended as a method of payment for those services, its value based on a fixed amount of ComStar service, transmission time, or delivery distance. Because of the uncertainty of the exchange rates for H-Bills, many mercenary units would request payments for their contracts be in C-Bills to ensure a consistent payment basis. As a result of this and interstellar trade in general, the C-Bill became a common currency throughout the Inner Sphere and the Periphery, in many places replacing the local H-Bills.

C-Bills are generally used in an electronic format, but are often commonly encountered as paper notes in denominations of 1, 5, 10, 50 and 100 units. Within territories administered by ComStar, coins called demis are issued. In external areas, local currency is used for sums smaller than 1 C-Bill.[3]

In 3025, the exchange rates for the various H-Bills and the C-Bill were as shown in the table below. This is a relative comparison only, as actual exchange rates would have varied daily. It should provide the reader with a view of the relative economic successes of the various houses.